first off welding aluminum is a bitch with a Tig welder...i would know...grrr...anyways check it out. just buy a new tranny from eBay or your local tranny shop. Go in and exchange your nasty old one for a nice new one! and there's no real difference b/w the USDM and JDM tranny's that i'm aware of...unless you want a cute little JDM plaque on her housing.